I'm in the same boat - can't find anything for May 23, but I was able to book for the 24th and 22nd. I get that what Disney does doesn't always make sense, and that maybe they're eating to finalize some special event plans before opening ADRs for Saturday, May 23.
However, everything I've read says that for the past 2 years, the 24 hour event has taken place from Friday morning at 6 am and lasted until Saturday morning at 6 am. So why would an event that takes place mostly on Friday affect ADRs on Saturday?